Simple signup function using FP-TS

Tom Liang — Wed, 29 Dec 2021 01:53:00 +0000

I tried to make a simple user signup function using FP-TS.

// user-controller.ts
import argon2 from "argon2";
import * as E from "fp-ts/Either";
import { flow, pipe } from "fp-ts/lib/function";
import * as TE from "fp-ts/TaskEither";
import {
    UserProfile,
    UserProfileRepository,
} from "../db/entities/user_profile";

function hashPassword(plainPassword: string) {
    return () => argon2.hash(plainPassword).then(E.right).catch(E.left);
}

export function signup(userName: string, email: string, password: string) {
    const makeUserProfile = (userPassword: string) =>
        new UserProfile({ userName, email, userPassword });
    return pipe(
        password,
        hashPassword,
        TE.chain(flow(makeUserProfile, UserProfileRepository.insertProfile))
    )();
}

How to call:

// user-router.ts
import express from "express";
import { pipe } from "fp-ts/lib/function";
import { signup } from "../controllers/user-controller";
import * as E from "fp-ts/lib/Either";

router.post("/signup", async (req, res) => {
    const { username, password } = req.body;
    const userE = await signup(username, username, password);
    pipe(
        userE,
        E.bimap(
            (e) => res.send({ ok: false, message: e.message }),
            (user) =>
                res.send({
                    ok: true,
                    message: `user ${user.userName} registered `,
                })
        )
    );
});

There must be better ways to compose the functions, will come back to it when I learn more.

User validation with Passport.js and fp-ts

Tom Liang — Thu, 23 Dec 2021 15:10:49 +0000

I had a first try on using fp-ts to do user validation with passport.js.

import argon2 from "argon2";
import * as E from "fp-ts/lib/Either";
import { flow, pipe } from "fp-ts/lib/function";
import * as O from "fp-ts/lib/Option";
import * as TE from "fp-ts/lib/TaskEither";
import * as passport from "passport";
import * as PassportLocal from "passport-local";
import logger from "./logger";
import {
    UserProfile,
    UserProfileRepository,
} from "../db/entities/user_profile";

const verifyPassport: PassportLocal.VerifyFunction = (
    userName: string,
    password: string,
    done
) => {
    const onUserFound = (optionUser: O.Option<UserProfile>) => {
        const onSome = (user: UserProfile) => () =>
            argon2
                .verify(user.userPassword, password)
                .then((valid) =>
                    valid
                        ? E.right(user)
                        : E.left(new Error(`invalid user name or password`))
                )
                .catch(E.left);
        const onNone = () =>
            TE.left(new Error(`user name ${userName} doesn't exist`));
        return pipe(optionUser, O.match(onNone, onSome));
    };
    pipe(
        userName,
        UserProfileRepository.findOneByUserName /*returns TE.TaskEither<Error, O.Option<UserProfile>> */,
        TE.chain(onUserFound),
        TE.bimap(
            ({ message }) => done(null, false, { message }),
            (user) => done(null, user)
        )
    )();
};

DEV Community: Tom Liang

Simple signup function using FP-TS

User validation with Passport.js and fp-ts